The present invention relates to a semiconductor wafer incorporating an electrically-isolated semiconductor device and, more particularly, to such a wafer wherein the electrical isolation of the semiconductor device is achieved through the use of semiconductor material integral with the wafer.
Semiconductor wafers having electrically isolated semiconductor devices contained therein are useful in that they permit the semiconductor devices to be operated at high voltage with respect to a substrate of the wafer that is typically at a ground (i.e., reference) potential. The semiconductor wafer, accordingly, can also integrally contain semiconductor devices that are operated at low voltage, such as signal level devices for processing low voltage information signals. This type of semiconductor wafer is, consequently, versatile in regard to the types of electrical functions it can perform.
A prior art semiconductor wafer incorporating an electrically-isolated semiconductor device achieves such electrical isolation by means of dielectric material that spaces the semiconductor device from a substrate of the wafer as well as from any further semiconductor devices in the wafer. Unfortunately, the fabrication of such wafers is complex and costly due to the incorporating of dielectric material to achieve electrical isolation. The use of semiconductor material for achieving the desired electrical isolation would result in a semiconductor wafer that is easier to fabricate and thus less costly than the prior art dielectric isolation approach. It would thus be desirable to provide a semiconductor wafer in incorporating an electrically isolated semiconductor device, with the electrical isolation achieved through the use of semiconductor material.